System and method for reducing interference between wireless charging and amplitude modulation reception

ABSTRACT

A method for reducing interference in an inductive charging system is provided. The method includes steps of inductively charging a chargeable device with an inductive charger, detecting the operation of a receiver in an AM band, and adjusting at least one of a frequency band employed by the charger and an amount of power provided to the chargeable device by the charger based on the operation of the receiver in the AM band.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/652,983, filed on Oct. 16, 2012, entitled “SYSTEM AND METHODFOR REDUCING INTERFERENCE DURING WIRELESS CHARGING.” The aforementionedrelated application is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to wireless charging systems,and more particularly, relates to reducing interference during wirelesscharging of portable devices in a vehicle.

BACKGROUND OF THE INVENTION

Portable battery operated electronic devices, such as cell phones,employ rechargeable batteries that must be recharged when battery chargeis consumed. Typically, electric-powered or electronic devices arephysically connected to an electrical charger via a wire connection.More recently, wireless charging devices such as inductive chargers areavailable to charge the battery without any physical wire connectionbetween the electronic device and the charging device. Wireless chargersgenerate an electromagnetic field through the use of electromagnetictransducers to transfer the electric energy from the charging device toa receiver on a battery or device having a battery being charged.Inductive chargers generate a magnetic field through the use ofinductive coils to transfer the electric energy from the charging deviceto a receiver on a battery or device having a battery being charged.Inductive chargers have been proposed for use on vehicles in variouslocations having a portable battery or a battery operated device withinthe cockpit of the vehicle, typically near the driver and otherpassengers, for the sake of convenience to allow easy access to thedevices. However, the electromagnetic field may potentially emit energyproducing frequency interference with other systems in the vehicle orbrought to the vehicle. Magnetic resonance chargers may also causeinterference, but the interference may be to a lesser degree. It istherefore desirable to provide a wireless charger within a vehicle in amanner that minimizes the introduction of frequency interference withother systems used in the vehicle.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a method for reducinginterference in an inductive charging system is provided. The methodincludes steps of inductively charging a chargeable device with aninductive charger, detecting the operation of a receiver in an AM band,and adjusting at least one of a frequency band employed by the chargerand an amount of power provided to the chargeable device by the chargerbased on the operation of the receiver in the AM band.

According to another aspect of the present invention, a charging systemfor reducing interference during inductive charging of a chargeabledevice is provided. The charging system includes an inductively poweredcharger and a controller configured to detect the selection of an AMtuning mode of a receiver in proximity to the charger. The chargingsystem adjusts the frequency band employed by the charger if thereceiver is tuned to a frequency within the predetermined portion of theAM band.

According to another aspect of the present invention, an in-vehiclesystem for reducing interference during inductive charging of achargeable device is provided. The in-vehicle system includes a chargerregion provided in a vehicle, an inductively powered charger and acontroller in communication with the inductive charger. The controllerdetects operation of a vehicle receiver in a scan mode of an AMfrequency band in proximity to the charger and adjusts a frequency bandemployed by the charger.

These and other aspects, objects, and features of the present inventionwill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a cockpit of a vehicle employing awireless charger at a potential charging region, according to oneembodiment;

FIG. 2 is an enlarged top view of a portion of the vehicle cockpitfurther illustrating the charging region located on a center console ofa vehicle with a portable chargeable device in proximity to the charger;

FIG. 3 is a block diagram of an inductive charging system, according toone embodiment;

FIG. 4 is a perspective view of an inductive charging system, accordingto one embodiment;

FIG. 5 is a schematic block diagram of a wireless charging systemconfigured to reduce interference between the inductive charging systemand other systems in a vehicle, according to one embodiment;

FIG. 6 is a table illustrating operations implemented by the wirelesscharging system based upon inductive charging protocol and operationmode, according to one embodiment;

FIGS. 7A and 7B are a flow diagram illustrating the frequency/poweradjustments routine for reducing interference in an inductive chargingsystem 1, according to one embodiment; and

FIG. 8 is a flow chart illustrating an operation implemented by thewireless charging system based on use of a radio in an AM band proximatethe wireless charging system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to a detaileddesign; some schematics may be exaggerated or minimized to show functionoverview. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring to FIGS. 1 and 2, the interior of an automotive vehicle 10 isgenerally illustrated having a passenger compartment 12 employing awireless inductive charging system 30, according to one embodiment ofthe present disclosure. The vehicle 10 generally includes a seatingarrangement including a front driver seat 14 and front passenger seat16, each adapted to seat a person as an occupant in the passengercompartment 12 of the vehicle 10. The vehicle 10 also includes a centerconsole 18 with a storage compartment 22 disposed between the frontseats 14 and 16 and side door armrests 21. The center console 18,dashboard 20, and armrests 21, as well as other vehicle assemblies, maybe equipped with various device holders, such as trays and storagecompartments that may receive one or more devices for wireless charging.The vehicle 10 may further include rear seating and wireless chargingtrays and storage compartments configured for wireless inductivecharging located in the rear seating area.

FIG. 2 illustrates an enlarged view of a portion of the interior of theautomotive vehicle 10 containing an inductive charging system 30. In theembodiment shown, a charging region 24 may be located on the centerconsole 18 of the vehicle 10 and a portable chargeable device 25 may beplaced on the surface of the charging system 30. The vehicle 10 may beequipped with one or more wireless charging systems 30 for wirelesslycharging one or more devices, including one or more rechargeablebatteries providing electrical power within an electronic device. In oneembodiment, one or more wireless charging systems 30 may be provided inone or more storage trays or dedicated trays provided in center console18. The wireless charging system 30 includes a wireless inductivecharger 26. Inductive chargers typically include one or more inductivecoils for generating electric signals in the form of an electromagneticfield (EMF) typically at low frequencies within a charging region 24. Inthe embodiment shown, the charging region 24 may be defined by a tray ora storage compartment having a bottom wall and side walls for receivinga device, such that the device, when located within the charging region24, may be charged via the electromagnetic field through inductivecoupling. According to another embodiment, the wireless charging system30 may use a charging region 24 provided on one or more pads or traysprovided in the vehicle dashboard 20. According to a further embodiment,the wireless charging system 30 may use a charging region 24, providedwith an inductive charger 26, located in a tray within the armrest 21extending from a vehicle door. In each of these embodiments, thewireless charging system 30 has a charging region 24 adapted to receiveone or more devices, such as rechargeable batteries or electric poweredor electronic devices 25 employing rechargeable batteries, that may becharged via an electric signal on the charging region and may beaccessible to the driver or other passengers within the cockpit 12 ofvehicle 10. Examples of electronic devices 25 that may be charged by thecharging system 30 include cell phones, computers, radios, lightingdevices, and music and video players.

Referring to FIG. 3, the wireless charging system 30 is furtherillustrated having control circuitry, shown in one embodiment as acontroller 40, including a microprocessor 42 and memory 44. Thecontroller 40 may include other or additional analog and/or digitalcircuitry. Stored within memory 44 may be a frequency/power adjustmentroutine 100 and adjustable frequency range and power charging parameters150. The controller 40 may receive, as inputs: 1) a signal indicative ofthe current charger state 30 (e.g., on or off); and 2) information via anetwork bus 50 relating to at least one of a detected interferingoperation mode of vehicle systems in proximity to wireless chargingsystem 30. The vehicle operation mode information may include frequencyband of a vehicle system (e.g., amplitude modulation/frequencymodulation (AM/FM) scanning or tuning of a radio), status informationfor a vehicle system such as active/inactive or in progress/to beinitiated, and positional information of a system in the vehiclerelative to controller 40. Detection of such modes of operation mayindicate that a device operating in such a mode would create or accept afrequency that would cause potential interference with vehicle systems.The interference can be in the form of radiated emissions and/orconducted emissions. Interference may also be generated by magneticresonance chargers since some manufacturers have solutions that operatein the kilohertz range and may have fundamentals or harmonics which maycause interference (e.g., via harmonics or fundamentals in the AMfrequency band). Such interference between vehicle devices and thecharger 30 may cause failure of the vehicle device, or the charger 30,to operate ineffectively, as well as the potential for a device undercharge to overheat by being overexposed to a particular frequency of thecharger 30. Following detection of a potential interfering mode ofoperation, the controller 40 may process this input information withrespect to the protective frequency/power adjustment routine 100 andgenerate an output to the inductive charger 26 having inductive coil(s)27 so as to at least reduce or prohibit the electrical charging signalto be generated by the charger 26 and/or adjust the frequency within thecharging region in order to avoid potential frequency interference withother vehicle modules.

FIG. 4 illustrates a possible implementation of a wireless inductivecharging system 30, according to some embodiments of the presentinvention. In FIG. 4, a transmitter section 110 may be housed in thecharging system 30. The transmitter section 110 may contain one or moretransmitter coils (not shown) which may be coupled to a connector thatis plugged into a standard external power source. A receiver 130 may behoused in a chargeable electronic device 25. The transmitter section 110may provide power to the receiver 130 such that the receiver 130provides power to a rechargeable battery and the transmitter section 110may receive additional control information from the receiver 130 toadapt to a particular power transfer based on the control information.

The vehicle charging system 30 may include one or more wireless chargersfor generating electric charging signals in the charger region 24 tocharge the electronic device 25 containing a rechargeable battery. Thewireless charger may include the inductive charger 26 generating anelectromagnetic field. The inductive charger may include one or moreinductive coils 27 located below or on the bottom surface of the chargerregion 24, such as a pad for generating an electromagnetic field in thecharger region 24. The electromagnetic field passes from inductive coils27 into the charger region 24 and is intended to wirelessly couple toone or more inductive receiver coils 120 provided in the portableelectronic device 25, so as to transfer electrical energy thereto forpurposes of charging one or more rechargeable batteries. As a result, anelectromagnetic field is present within the charger region 24.

FIG. 5 shows a schematic illustration depicting one embodiment of anadaptable wireless communication system including a network connectionbetween the wireless charging system 30 and a vehicle access, and astart system, including a plurality of additional features integrated inthe vehicle. The charging system 30 may interface with a plurality ofnetworks via the vehicle network bus 50, such as a privately accessiblenetwork such as WAN/LAN, publicly accessible networks, such as theInternet, in-vehicle networks, such as Controller Area Networks (CAN)and Assembly Line Data Link (ALDL). When the charging system 30 isconnected to an in-vehicle data bus 50, the controller 40 in thewireless system 30 may accept in-coming operation mode information fromother vehicle devices connected to the in-vehicle data network, such asfrequency band information, status information, such as active/inactiveand indication of progress/initialization, and positional information ofa device relative to system 30. In addition, when connected to anin-vehicle data network, the controller 40 may monitor the in-comingoperation mode information from other vehicle electronic devices andsystems connected to the network as well as operating frequency of thesystem 30. Depending on the operation mode detected by the controller40, the controller 40 may issue commands modifying the chargingfrequency of the charger 26 and/or the amount of power used by thecharger 26 to charge the rechargeable battery or batteries of theportable device 25 by adjusting the electrical charging signal generatedby the charger 26.

As shown in one embodiment in FIG. 5, the in-vehicle data bus 50 allowsfor communication between the wireless charging system 30 and variouscomponents integrated within the vehicle 10, such as a cellular receiver52, a vehicle access and start controller 54, an AM/FM receiver 56, anda hands-free cellular 911 Assist controller 58. The controller 40 withinthe wireless charging system 30 may be instructed to charge wirelessdevices 25 at a particular frequency band, depending on the type ofinductive charging protocol that a device 25 responds to. Some examplesof inductive charging protocols that a charging system 30 may beequipped with are: Qi Wireless Power Consortium (WPC), which may operateon a low frequency band of 90 kHz-205 kHz, Powermat Generation 2, whichmay also operate on a low frequency band of 90 kHz-205 kHz, and PowermatGeneration 1, which may operate on a low frequency band of 270 kHz-370kHz. Similarly, Qi magnetic resonance solutions operate in approximatelythe same frequency band as a Qi magnetic induction (i.e., inductive)charging solution. Other inductive charging protocols and otheroperating frequencies may be employed. In a specific embodiment, thecharger 26 may operate at a charging frequency of about 110 kHz.

A cellular receiver 52 may be contained within a cellular device that isequipped inside the vehicle 10. The receiver 52 may also allow the userto receive phone calls from any remote phone and transmit phone callsfrom an integrated vehicle 10 by operating at a frequency of 850 MHz to1900 MHz, depending on the type of mobile standard (such as GSM or CDMA)on which the cellular device operates. The cellular receiver 52 maybroadcast a message to the charging system 30 over the vehicle bus 50indicating that the vehicle cellular device is receiving andtransmitting data and may be susceptible to a potential interferingfrequency from the operating band of the inductive charger system 30.Alternatively, the operating frequency of the cellular receiver 52 maybe measured by a vehicle access and start controller 54 and the vehicleaccess and start controller 54 may broadcast a message over the vehiclebus 50 to the charging system 30, indicating that the cellular device isoperating at a frequency that may be susceptible to potentialinterference from the operating frequency of inductive charger 30.

The AM/FM receiver 56 may be contained within a vehicle radio (notshown) that is equipped inside the vehicle 10. The AM/FM receiver 56 maysupport North American FM bands operating at a frequency of 88 MHz to108 MHz and North American AM bands operating at a frequency of 520 kHzto 1610 kHz, as well as other worldwide audio bands, such as long waveand NOAA weather band. The AM/FM receiver 56 may broadcast a message tothe charging system 30 over the vehicle bus 50 indicating the vehicleradio is tuned to a station with a frequency band that would potentiallysee interference from the operating frequency of the charging system 30.Alternatively, the operating frequency of the AM/FM receiver 56 may bemeasured by a vehicle access and start controller 54. If the vehicleaccess and start controller 54 determines the operating frequencyreaches a certain threshold, it will broadcast a message over thevehicle bus 50 to the charging system 30 indicating the receiver 56 isoperating at a frequency that potentially may see interference from theoperating frequency of the inductive charger 30.

The 911 Assist controller 58 contained within a 911 Hands-Free CellularAssist System (not shown) may be equipped inside the vehicle 10. The 911Hands-Free Cellular Assist System may synchronize with a driver'scellular device allowing for hands-free cellular phone capabilitieswhile driving and also connecting the driver directly to a local 911operator in the event an accident is detected within the vehicle (forexample, vehicle airbags deploy or emergency fuel pump shutoff isactivated). This feature may deliver a voice message to operatorsindicating the vehicle has been in an accident. If an accident occurswhile the driver is using the hands-free phone capabilities, the 911Assist System would automatically end that call and dial 911. If anoccupant of the vehicle is unable to communicate with the 911 operator,a message sent by the Assist System tells the 911 operator that anaccident has occurred and location information provided by the mobilephone carrier is given to the operator. If a 911 Assist Call is eitherin progress or about to be initiated, the 911 Assist controller 58 maybroadcast a message to the inductive charging system 30 over the vehiclebus 50 indicating the charging of a mobile device 25 is to be suspendedin order to reduce the probability that the inductive charger 30 willinterfere with the 911 Assist Call. An example of a 911 Hands-FreeCellular Assist System is Ford Motor Company's SYNC® 911 Assist feature,which may be equipped onto Ford's vehicles.

Once the controller 40 receives from the network bus 50 status messagesfrom a vehicle module, such as the cellular receiver 52, vehicle accessand start controller 54, AM/FM receiver 56, and 911 Assist controller58, the controller 40 will process the input information with respect toa routine 100 stored in memory 44 executed by control circuitry which inturn will adjust the electrical charging signal frequency and/oramplitude to be generated by the charger 26 in order to avoid potentialinference with other vehicle modules.

The table shown in FIG. 6 illustrates one embodiment of actions that maybe affected by the frequency/power adjustment routine 100 of thewireless charging system 30, depending on the type of inductive chargingprotocol device 25 responsible to the protocol and the mode of operationof vehicle modules detected by the charging system 30. FIG. 7 shows ageneral flow chart illustrating the various steps of the adjustmentroutine 100 that may be executed by the controller 40 based upon themapping shown in FIG. 6.

Referring to FIG. 7, the routine 100 begins at step 202 and maydetermine if the wireless charger is on and proceeds to step 204. Instep 204, the controller 40 determines whether a potential object hasbeen detected on the surface of the charging system 30 and if the objectdetected is capable of being charged inductively by the system 30. If instep 204, the controller 40 determines these conditions have been met,the controller 40 advances to step 206. Otherwise, the controller 40returns to step 204 to determine whether a new target object has beendetected on the surface of system 30 and whether the object detected canbe charged inductively.

In step 206, the controller 40 determines if the object meets certainthresholds for size and/or mass. In this step, the controller 40determines if the size and/or mass of the object detected is within athreshold criteria where it is expected that the object may be a deviceexpecting to be charged by the charging system 30. If the object doesnot fall within the threshold criteria, the controller 40 advances tostep 208 in which it ignores the object without giving notice to theuser and returns to step 204 to determine whether a new target objecthas been detected on the surface of charging system 30 and whether theobject detected can be charged inductively. If the object does meet thethreshold criteria of step 206, the controller 40 advances to step 210.By not generating any energy until a potential receiver of a chargeabledevice has been detected, the system reduces the occurrence of potentialbroadcast radio frequency noise and mitigates the risk of interferencefrom non-chargeable devices being left on the charging system 30.

In step 210, the controller 40 determines whether a synchronized 911Assist Call is in progress. The controller 40 advances to step 216 ifsynchronized 911 Assist is not in progress. If the Assist Call is inprogress, the controller 40 then proceeds to 214 to decide whether a)the power remaining in the portable device, such as cellular device 25,falls below a predetermined X % or b) the power level of the cellulardevice 25 cannot be read. If neither of these conditions are met, thecontroller 40 proceeds to step 212 in which charging becomes suspendedunless the State of Charge (SOC) of the phone falls below X % and thenproceeds back to step 210 in order to keep the cellular device 25charging and active while the 911 Assist call is in progress. As alsonoted in Vehicle Operation Mode 10 of FIG. 6, charging is suspendedirrelevant of the system 30 wireless charging protocol usage. Steps 210,212 and 214 assist in reducing the probability of frequency interferencebetween the 911 Assist Call and the operating frequency of the chargingsystem 30 during charging. Additionally, steps 212 and 214 account forsituations where suspension of the charge should not be activateddespite the potential for frequency interference from an activelycharging device 25 while 911 Assist is in progress or to be initiated.These type of situations occur when the SOC falls below a predeterminedX %, such as 40%, where it would be imprudent to suspend charging belowthe predetermined X % level. Suspending charging below such apredetermined X % level may not give the cellular device 25 sufficientpower to fully complete the 911 Assist operation or to allow foradditional calls using the 911 Assist Call if the initial 911 AssistCall fails. If, in step 306, the controller 40 determines that thewireless technology standard reading can be obtained and power is notless than X %, the controller 40 advances to step 216.

In step 216, the controller 40 outputs a visual indication to the userthat the “Charging Session Assessment” is in-progress. The visualindication may be disposed upon the charging region 24 and/or elsewherein the charging system 30 or the vehicle 10. The controller 40 nextadvances to step 218 to initiate determination of the type of inductivecharging protocol that the device 25 may respond to and with which thecharging system 30 may be equipped. Each inductive charging protocoloperates to generate charging power at a predetermined frequency band.For example, Qi Wireless Power Consortium (WPC) and Powermat Generation2 may operate on a low frequency band of 90 kHz-205 kHz, whereasPowermat and Powermat Generation 1 may operate on a low frequency bandof 270 kHz-370 kHz.

The controller 40 next determines in step 220 whether the chargeabledevice 25 responds to a first protocol ping. In this step, thetransmitter circuit 110 of the charging system 30 will attempt tocommunicate with the receiver 130 of the rechargeable device 25 bysending a digital ping (a short periodic test pulse) to the receiver130. After transmission of the digital ping, if the receiver 130 sendsan appropriate feedback signal back to transmitter 110, this indicatesthe receiver is a valid, first protocol compliant system and thecontroller 40 will proceed to step 222. If the device does not respondto a first protocol ping, the controller 40 proceeds to step 252 todetermine if the device responds to a second protocol ping. For example,in step 220, the controller 40 may attempt to communicate with thedevice 25 via a Qi standard compliant ping. If chargeable device 25 isnon-responsive to the Qi compliant ping, the controller 40 may thenattempt to communicate with the device 25 via a Powermat compliant ping.If the chargeable device does not respond to either a first protocolping or a second protocol ping, the controller 40 may indicate to theuser that a “compatible device was not detected” in step 254 and proceedback to step 204 to detect whether another potential object is on or inproximity to the charging system 30. In other embodiments, there may beadditional steps after step 252 testing if the chargeable device 25responds to additional protocol pings.

In another embodiment, the charging system 30 may visually indicate tothe user that the system is first protocol or second protocol compliant.For example, following satisfaction of step 220 or 252, the chargingsystem 30 may output a visual indication upon the charging region 24and/or charging system 30 to a user that the chargeable device is “QiCompliant” or “Powermat Compliant.” Such a visual indication may takethe form of a logo or trademark representing the inductive chargingprotocol that the chargeable device 25 was found compliant with.

If chargeable device 25 responds to either the first protocol ping orthe second protocol ping, the controller 40 then proceeds to step 222 todetect if a plurality of other electronic devices within the vehicle 10are installed, including a vehicle access and start system and/or avehicle radio AM/FM band. The controller 40 next, in step 224,configures the charging system 30 based upon operation modes labeled 0or 1 if the vehicle access and start system or vehicle radio AM/FM bandis detected as uninstalled or inactive. Otherwise, the controller 40proceeds to step 228. Such detection in step 222 may be a message from aseparate module in the vehicle communicating to the controller 40 of thecharging system 30 the uninstalled or inactive state of the vehicleaccess and start system and vehicle radio. In another embodiment, it maybe assumed that if the controller 40 does not receive any messages fromthe vehicle modules to operate in a different mode within apredetermined time, then controller 40 will communicate to the chargingsystem 30 to charge the portable device 25 based upon operation modes 0or 1.

Details of an example of operation modes 0 or 1 are described below withrespect to FIG. 6. As shown in FIG. 6, if the vehicle operation modecommunicated to the controller 40 via the vehicle bus 50 indicates nofactory equipped vehicle access and start system (mode 1) or the vehicleis off, AM/FM band is off, or no vehicle access and start system isactivated (mode 2), then the controller 40 will instruct the inductivecharger 26 to charge the portable device 25 on full LF band, dependingon the type of protocol with which the system 30 is operating. Forexample, if system 30 operates on a Qi Wireless Power Consortium (WPC)protocol, the charging system 30 would be instructed to charge theportable device 25 at a low frequency band of 90 kHz-205 kHz duringoperation modes 0 or 1. The operating frequency does not need to beadjusted during detection of operation modes 0 or 1 because mitigationof frequency band interference between the vehicle modules and thecharging system 30 will not be an issue if the vehicle modules areuninstalled or inactive.

Following configuring the inductive charging system 30 based onoperation mode 0 or 1, the controller 40 proceeds to step 226 to chargethe portable device 25 at full LF band and to provide visualnotification to the user of the percent charge completed of thechargeable device 25. The visual indication may be disposed upon thecharging region 24 and/or elsewhere in the charging system 30 or thevehicle. The controller 40 next advances to step 228 to determinewhether the 911 Assist call has been initiated. If the 911 Hands-FreeCellular Assist feature has been initiated, then the controller 40 loopsback to step 212 in which charging becomes suspended unless the State ofCharge (SOC) of the phone falls below X %. The controller 40 thenproceeds to step 210 in order to keep suspension of the charge activewhile the 911 Assist Call is in progress. As noted above, whilesuspending charging lowers the potential for frequency interferencebetween the charging device 25 and the in-progress or to be initiated911 Assist, suspension of charging should not be activated when thedevice 25 may not have sufficient power to fully complete the 911 Assistoperations.

If, in step 228, the controller 40 determines the 911 Assist Call hasnot been initiated, the controller 40 advances to step 230 to determineif the AM radio is activated at tuner frequencies greater than or equalto a predetermined P kHz. For example, P may be a threshold frequency of825 kHz. With reference to FIG. 6, if the AM radio is activated, it maysend a message to the controller 40 communicating that a particular bandis active at a particular frequency range either greater than or equalto a predetermined P kHz or less than a predetermined P kHz.Alternatively, the operating frequency of the AM receiver 56 may bemeasured by a vehicle access and start controller 54 and the vehicleaccess and start controller 54 may broadcast a message over the vehiclebus 50 to the charging system 30 indicating the AM radio is operating ata frequency that is interfering with the operating frequency of theinductive charger 30. If the AM band is detected as active by thecontroller 40, the controller 40 proceeds to step 232 and adjusts theoperating frequency of the charging system 30 depending on vehicleoperating modes labeled 2 and 3 and the type of inductive protocoldetermined in steps 220 and 252. As shown in one embodiment in FIG. 6,for example, if AM radio is operating at a tuner frequency less than PkHz, this information is reported to the controller 40, and if it isdetermined that the device 25 responds to a second protocol, thecontroller 40 will provide instructions to shift down the operatingfrequency by a factor of four (column 2, row 3) when delivering power tothe charging coil 27 of the charger 26. The controller 40 then advancesback to step 228 to determine if the 911 Assist Call has been initiatedand continues to loop between steps 228, 230, and 232 as long as the AMband is detected as active. In addition, if the charging system 30receives a broadcast message from the bus 50 indicating the radio is innon-AM mode, such as MP3 mode or FM mode, then the charging system 30would charge at full LF band without restriction and the controller 40would proceed to step 234.

As noted above, if the AM band is inactive at particular tunerfrequencies, the controller 40 proceeds to step 234 to determine if avehicle access and start system query has been initiated. The vehicleaccess and start system may provide a plurality of automated functionswithin the vehicle 10 depending on user input, including, but notlimited to, allowing drivers to unlock a vehicle by touching a doorhandle and/or to start the vehicle. The vehicle access and start systemmay include signal receivers and antennas for processing user input andgranting user access. The vehicle access and start system may becontrolled by a separate module such as the vehicle access and startcontroller 54 located within the vehicle 10. Interactions betweenvehicle access and start controller 54 and a driver held key fob mayoccur at a frequency band that may conflict with the operating frequencyof the charging system 30. For example, the vehicle access and startsystem may communicate with the key fob at a frequency of 125 kHz(Amplitude Shift Key data pulses) and the fob may communicate with thevehicle access and start system at 315 MHz or 901 MHz. If the fob isplaced too close to the system 30, the key fob may sense a vehicle 125kHz signal due to the 125 kHz energy emitted from the system 30 duringcharging. In addition, the vehicle access and start system may not begincommunication with the key fob unless a particular START, ENTRY orSTATUS CHECK condition has been sensed by the system such as theactivation of a door handle switch, pushing of a start button, releasingof a brake, or opening of a door.

In step 234, when the vehicle access and start system has beeninitiated, the vehicle access and start controller 54 may broadcast amessage over the bus 50 to the controller 40 indicating the vehicleaccess and start system initiation, and the controller 40 will proceedto step 236. As shown in FIG. 6, if, in step 236, the controller 40receives a message indicating the vehicle access and start controller 54is attempting, for a first time, to communicate with a user held keyfob, the controller 40 may hold the LF band setting, but reduce theamount of power used to charge the portable device 25, for apredetermined amount of time. Such a power reduction may occur while thesystem 30 is operating in a first inductive protocol or a secondinductive protocol, but operating in a third inductive protocol mayallow the system to charge the device 25 without restriction, as shownin FIG. 6. If, in step 236, the controller 40 receives a messageindicating the vehicle access and start controller is attempting, for asecond time, to communicate with a driver held key fob, the controller40 may hold the LF band setting but suspend charging of the devicecompletely for a predetermined amount of time (vehicle operation mode 8in FIG. 6).

In another embodiment, if the controller 40 receives a messageindicating the vehicle access and start controller 54 is attempting, fora first time, to communicate with a user held key fob, the controller 40may exclude a particular frequency band from charging the device 25(vehicle operation mode 4 in FIG. 6). For example, if the key fobcommunicates to the vehicle controller 54 at 125 kHz, then the vehiclecontroller 54 will broadcast an indication of this fact via a datapacket to the controller 40 of the inductive charging system 30. Thecontroller 40 may then operate to delete the frequency band around 125kHz (115-135 kHz band), thereby allowing the charging system 30 tooperate on a non-impeded frequency band. Following reduction orsuspension of the inductive charging power (steps 238 or 240), oradjustment of the frequency of the charging system 30, depending onvehicle operating modes 2 and 3 (step 232), the controller 40 loops backto step 228 to determine if a 911 Assist Call has been initiated andcontinues to loop between steps 228, 230, and 232 as long as the AM bandis detected as active.

In another embodiment, an operation for excluding a particular frequencyband may depend on the location of the key fob relative to the vehicleaccess and start system (vehicle operation mode 5, FIG. 6). For example,after vehicle access and start system has been initiated in step 234, itmay triangulate the positional coordinates of the key fob to determineif the key fob is a predetermined distance away from the device 25 thatis being charged by the system 30. If the key fob is determined to notbe within a distance from the device 25, such that there lacks the riskof interfering with the operation of vehicle access and start system,then the charging system 30 can continue to operate on its full LF band.If the key fob is determined to be within a distance from the device 25,such that there would be a risk of interfering with the operation of thevehicle access and start system, then the controller 40 may continue toexclude the particular frequency band from charging the device 25(vehicle operation 5, FIG. 6).

Either reducing/suspending the amount of power charging of the device25, or removing the particular frequency band that the system 30 isoperating in, will facilitate in reducing the risk that thecommunicating frequency between the key fob and vehicle controller 40will be obstructed by the noise caused from inductively charging thedevice 25. However, removing the band or decreasing the power may alsoreduce the efficiency of the inductive charging of the device 25.Therefore, if, in step 234, a vehicle access and start system query hasnot been detected as initiated, the frequency band will not be removed,and the controller 40 will proceed to step 242.

The controller 40 next determines in step 242 whether the chargeabledevice 25 has been misaligned on the charging system 30. Misalignmentmay be detected when the device 25 slides out of place to a positionthat results in the transmitter and receiver coils being offset by up toas much as 12 mm without a charging session termination because of alack of detected communication between the transmitter and receiver.Misalignment may occur because the chargeable device 25 slides off of anoptimal charging position while the vehicle is in motion. Depending onthe shape of the phone and the amount of offset, misalignment may resultin higher EMF energy radiating from the charging system 30 duringcharging because of less optimal blocking of such EMF energy from thephone receiver assembly (i.e. receiver coil and ferrite plate). HigherEMF energy radiating from the system 30 may increase the potential forinterference with other systems. Thus, when the controller 40 detectsthe device 25 is misaligned, the controller 40 proceeds to step 244 tohold the LF band setting, but reduces the amount of power charged to thedevice 25 by a predetermined percentage (operation mode 6, FIG. 6).Reducing the amount of charge will reduce the amount of EMF energyradiating from the charging system 30. The controller 40 then loops backto step 228 to determine if 911 Assist Call has been initiated.

If the controller 40 determines the device 25 is not misaligned, then itproceeds to step 246 to visually indicate an update of the chargingstatus to the user. Such visual indication may show a new percentagecharge completed for the device 25. The controller 40 then proceeds tostep 248 to determine if the charging of the device 25 has beencompleted. If not, then the controller 40 loops back to step 246 todetermine the charging status of the display. When charging of thedevice 25 has been completed, the controller 40 proceeds to step 250 tovisually indicate to the user that the charging event has been completedand then proceeds to the end process.

Referring now to FIG. 8, a method 300 is shown that may be executed bythe controller 40 and is generally used when the receiver 56 of theradio is operating in the AM band and the charger 30 is charging thechargeable device 25. Operating the receiver 56 in the AM band maypresent a number of challenges while the charger 30 is operating.Integer multiples, or harmonics, of the charging band frequency of thecharger 30 may form interference onto which the receiver 56 will lock.For example, if the fundamental charging frequency of the charger 30 is110 kHz, the charging will emit harmonics of decreasing amplitude ininteger multiples of 110 kHz such as 220 kHz, 330 kHz, 440 kHz, 550 kHz,etc. These integer multiples may extend and radiate through the AM band,causing the receiver 56 to lock on them and prevent the driver or otheruser in the vehicle 10 from efficiently scanning the AM band.

Method 300 begins with step 304 of detecting activation of the AM bandwhen the charger 30 is active. The AM band may be activated via aphysical button, switch, knob, a virtual button on ahuman-machine-interface or the like, voice command, as part of anothersequence of events, or other method of activation. The AM band may beactivated in a plurality of modes, including a scanning mode and atuning mode. In the scanning mode, the driver or user initiates the AMband scanning mode and the AM/FM receiver 56 begins automaticallyscanning through AM frequencies (e.g., in an increasing or decreasingprogression) from a start point (e.g., a predetermined AM frequency orthe last used frequency) and stops or settles (e.g., either briefly orpermanently) on a frequency which has a signal. In the tuning mode, thedriver or user may manually advance through the frequencies or the AMband and settle on a desired frequency. Once the receiver 56 isactivated in the AM band, the receiver 56 sends a signal to thecontroller 40 indicating activation of the AM band. It will beunderstood that although method 300 is explained as being initiated whenthe AM band is activated during charging of the chargeable device 25,method 300 may also be initiated by charging of the chargeable device 25while the receiver 56 is already active in the AM band.

Once the controller 40 detects the activation of the AM band, step 308of adjusting the charging band frequency and/or power of the charger 30is performed. In various embodiments, immediately after the controller40 senses the selection of the scanning mode or the tuning mode in theAM band, the charging band frequency of the charger 30 is shifted (e.g.,up or down in frequency) by a predetermined amount (e.g., 2.5 kHz), asexplained above. In other embodiments, the shift in charging bandfrequency of the charger 30 may be delayed. Additionally oralternatively to a frequency shift of the charging band frequency, thecharger 30 may reduce the charging power it supplies to the chargeabledevice 25 upon indication that the AM band is activated. The powertransferred from the charger 30 to the chargeable device 25 may becompletely eliminated (i.e. no charging) or reduced to about the minimumpower needed to maintain charging of the chargeable device 25 asexplained above.

In some embodiments of the tuning mode, prior to shifting of thecharging band, frequency of the charger 30 is delayed to determine ifthe tuning frequencies are in a predetermined portion of the AM band.The predetermined portion of the AM band may cover a range of AM bandfrequencies in which integer multiples of the charging band frequencyare likely to be present and cause interference with the receiver 56.Exemplary ranges for the predetermined portion of the AM band range fromabout 100 kHz to about 1500 kHz, from about 200 kHz to about 1000 kHz,and from about 540 kHz to about 900 kHz. If the sensed tuningfrequencies of the tuning mode fall within the predetermined portion ofthe AM band, the controller may then immediately shift the charging bandfrequency of the charger 30 as explained above. In various embodiments,if the tuning frequencies are on a threshold (e.g., with about 100 kHzof the upper or lower frequencies of the predetermined portion) oroutside of the predetermined portion, the charger 30 may maintain thestandard or normal charging band frequency and power.

Next, in step 312, the controller 40 determines whether or not thereceiver 56 has settled on a frequency. In various embodiments, thecontroller 40 may determine that the receiver 56 has settled on afrequency when the receiver 56 has been tuned to that frequency for apredetermined amount of time. For example, the predetermined amount oftime may be between about 0.11 second and about 25 seconds, betweenabout 1 second and about 20 seconds, and in a specific embodiment about15 seconds.

Next in step 316, once the controller 40 has determined that thereceiver 56 is settled on a frequency, the controller 40 determines ifthe frequency chosen is an integer multiple of the charging bandfrequency. If the settled on frequency by the receiver 56 is an integermultiple of the charging band frequency of the charger 30, thecontroller 40 may keep the charger 30 at the adjusted frequency and/orpower level.

If the controller 40 determines that the settled on frequency is not aninteger multiple of the charging band frequency, the controller 40transitions to step 320. In step 320, the controller 40 adjusts thecharging band frequency and/or power back to the normal or optimalcharging conditions for the charger 30 and chargeable device 25. In someembodiments, based on the settled on frequency of the receiver 56, thecharging frequency and/or power of the charger 30 may not be shiftedback to the optimal configuration, but may be altered.

Accordingly, the wireless inductive charging system 30 advantageouslyreduces or prohibits emission of energy from radiating at certaincharging frequencies or operating at certain power levels within acharging region. This advantageously prevents the electromagnetic fieldcreated by the charger during wireless charging from interfering withthe operation of other devices or systems in its proximity. The wirelesscharging system 30 is particularly well suited for use on a vehiclewhere there are many electronic devices that may operate on a similarfrequency band as the wireless system. However, the system may be usefulfor other applications. It should be appreciated that when the object isno longer detected as interfering with other devices, the wirelesscharging may be increased and resumed.

It is to be understood that variations and modifications can be made onthe aforementioned structure without departing from the concepts of thepresent invention, and further, it is to be understood that suchconcepts are intended to be covered by the following claims unless theseclaims by their language expressly state otherwise.

What is claimed is:
 1. A method for reducing interference in aninductive charging system, the method comprising: inductively charging achargeable device with an inductive charger; detecting the operation ofa receiver in an AM band; and adjusting at least one of a frequency bandemployed by the charger, and an amount of power provided to thechargeable device by the charger, based on the operation of the receiverin the AM band.
 2. The method of claim 1, wherein the receiver has atleast one of a scan mode or a tunable mode of operation in the AM band.3. The method of claim 1, further comprising the step of detecting thereceiver settling on a frequency in the AM band for more than apredetermined amount of time.
 4. The method of claim 3, furthercomprising the step of determining if the settled on frequency is aninteger multiple of the frequency band at which the inductive chargercharges the chargeable device.
 5. The method of claim 4, furthercomprising the step of adjusting at least one of the frequency bandsemployed by the charger, and the amount of power provided to thechargeable device by the charger, if the settled on frequency is not aninteger multiple of the frequency band at which the inductive chargercharges the chargeable device.
 6. The method of claim 5, wherein theadjustment of at least one of the frequency bands employed by thecharger, and the amount of power provided to the chargeable device bythe charger, is adjusted back to a normal operating frequency and anormal operating power if the settled on frequency is not an integermultiple of the frequency band of operation of the charger.
 7. Themethod of claim 1, wherein the adjustment of the amount of powerprovided to the chargeable device by the charger lowers the amount ofpower provided to about a minimum power needed to maintain charging ofthe chargeable device.
 8. A charging system for reducing interferenceduring inductive charging of a chargeable device, comprising: aninductively powered charger; and a controller configured to detect theselection of an AM tuning mode of a receiver in proximity to the chargerand adjust a frequency band employed by the charger if the receiver istuned to a frequency within a predetermined portion of the AM band. 9.The charging system of claim 8, wherein the controller adjusts an amountof power provided to the chargeable device by the charger.
 10. Thecharging system of claim 9, wherein the adjustment of the amount ofpower provided to the chargeable device by the charger is to about aminimum power needed to maintain charging of the chargeable device. 11.The charging system of claim 8, wherein the predetermined portion of theAM band extends from about 200 kHz to about 1000 kHz.
 12. The chargingsystem of claim 11, wherein the predetermined portion of the AM bandextends from about 540 kHz to about 900 kHz.
 13. The charging system ofclaim 8, wherein the controller detects the receiver settling on afrequency in the predetermined portion of the AM band for more than apredetermined amount of time.
 14. The charging system of claim 13,wherein the controller is configured to determine if the settled onfrequency is an integer multiple of the frequency band at which thecharger charges the chargeable device.
 15. An in-vehicle system forreducing interference during inductive charging of a chargeable device,comprising: a charger region provided in a vehicle; an inductivelypowered charger; and a controller in communication with the inductivecharger, wherein the controller detects operation of a vehicle receiverin a scan mode of an AM frequency band in proximity to the charger andadjusts a frequency band employed by the charger.
 16. The system ofclaim 15, wherein the controller adjusts an amount of power provided tothe chargeable device by the charger to about a minimum power needed tomaintain charging of the chargeable devices.
 17. The system of claim 15,wherein the controller detects the receiver settling on a frequency inthe predetermined portion of the AM band for more than a predeterminedamount of time.
 18. The system of claim 17, wherein the controller isconfigured to determine if the settled on frequency is an integermultiple of the frequency band at which the charger charges thechargeable device.
 19. The system of claim 18, wherein the controller isconfigured to adjust at least one of the frequency bands employed by thecharger, and the amount of power provided to the chargeable device bythe charger, if the settled on frequency is not an integer multiple ofthe frequency band at which the inductive charger charges the chargeabledevice.
 20. The system of claim 15, wherein the charger inductivelycharges the chargeable device at a charging frequency having harmonicsin the AM frequency band.